A mesh, peer-to-peer, cluster-tree, hierarchical personal area network (PAN) technology is well suited to a wide range of building automation, industrial, medical and residential control & monitoring applications. Examples of common applications include (by way of example and not limitation):
Lighting controls;
Automatic Meter Reading;
Wireless smoke and CO detectors;
HVAC control;
Heating control;
Home security;
Environmental controls;
Blind, drapery and shade controls;
Medical sensing and monitoring;
Industrial and building automation.
ZigBee™ is one example of a conventional mesh, peer-to-peer, cluster-tree, hierarchical personal area network (PAN) topology. According to zigbee.org, ZigBee is the name of a specification for a mesh, peer-to-peer, cluster-tree, and hierarchical network topology and set of protocols using that topology. The ZigBee technology utilizes small, low-power digital radios based on the Institute of Electrical & Electronics Engineers (IEEE) 802.15.4 standard for wireless personal area networks (WPANs). A WPAN is a wireless computer network used for communication among computer devices located in very close proximity to each other; typically the range is that which is close to a person. Typically, the reach of a WPAN is a room (e.g., 50-100 metres).
In the case of a typical mesh, peer-to-peer, cluster-tree, and hierarchical PAN topology, there are often intermediary levels where nodes function as routers. These so-called router-nodes are allocated fixed blocks of network address space that they then further allocate to their children nodes. Under this conventional approach of the static allocation of address blocks, when a new terminal node wants to join an existing PAN, that node must request admission and receive an address on that network. This new node might be a node that had left the network at some other physical point and wants to rejoin at another. Alternatively, the new node may be entirely new to the network.
If the node is close to another router-node in the network, the conventional network management typically tries to allocate addresses to the new node from the fixed address space assigned to the router-node. If the fixed address space is already used up, the network does not admit the new node. Although there may be other router-nodes with unallocated address space, this new node is refused admission to the network because the in-range router-node—through which the new node is attempting to access the network—has exhausted its statically allocated fixed addresses.
This situation occurs with conventional mesh, peer-to-peer, cluster-tree, and hierarchical PAN standards (such as ZigBee) because such conventional approaches use an inflexible static allocation of address space to nodes and router-nodes in the networks hierarchical topology.